1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Optimized MPEG FS - inode and super operations.
4 * Copyright (C) 2006 Bob Copeland <me@bobcopeland.com>
5 */
6 #include <linux/module.h>
7 #include <linux/sched.h>
8 #include <linux/slab.h>
9 #include <linux/fs.h>
10 #include <linux/vfs.h>
11 #include <linux/cred.h>
12 #include <linux/buffer_head.h>
13 #include <linux/vmalloc.h>
14 #include <linux/writeback.h>
15 #include <linux/seq_file.h>
16 #include <linux/crc-itu-t.h>
17 #include <linux/fs_context.h>
18 #include <linux/fs_parser.h>
19 #include "omfs.h"
20
21 MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>");
22 MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");
23 MODULE_LICENSE("GPL");
24
omfs_bread(struct super_block * sb,sector_t block)25 struct buffer_head *omfs_bread(struct super_block *sb, sector_t block)
26 {
27 struct omfs_sb_info *sbi = OMFS_SB(sb);
28 if (block >= sbi->s_num_blocks)
29 return NULL;
30
31 return sb_bread(sb, clus_to_blk(sbi, block));
32 }
33
omfs_new_inode(struct inode * dir,umode_t mode)34 struct inode *omfs_new_inode(struct inode *dir, umode_t mode)
35 {
36 struct inode *inode;
37 u64 new_block;
38 int err;
39 int len;
40 struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);
41
42 inode = new_inode(dir->i_sb);
43 if (!inode)
44 return ERR_PTR(-ENOMEM);
45
46 err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,
47 &new_block, &len);
48 if (err)
49 goto fail;
50
51 inode->i_ino = new_block;
52 inode_init_owner(&nop_mnt_idmap, inode, NULL, mode);
53 inode->i_mapping->a_ops = &omfs_aops;
54
55 simple_inode_init_ts(inode);
56 switch (mode & S_IFMT) {
57 case S_IFDIR:
58 inode->i_op = &omfs_dir_inops;
59 inode->i_fop = &omfs_dir_operations;
60 inode->i_size = sbi->s_sys_blocksize;
61 inc_nlink(inode);
62 break;
63 case S_IFREG:
64 inode->i_op = &omfs_file_inops;
65 inode->i_fop = &omfs_file_operations;
66 inode->i_size = 0;
67 break;
68 }
69
70 insert_inode_hash(inode);
71 mark_inode_dirty(inode);
72 return inode;
73 fail:
74 make_bad_inode(inode);
75 iput(inode);
76 return ERR_PTR(err);
77 }
78
79 /*
80 * Update the header checksums for a dirty inode based on its contents.
81 * Caller is expected to hold the buffer head underlying oi and mark it
82 * dirty.
83 */
omfs_update_checksums(struct omfs_inode * oi)84 static void omfs_update_checksums(struct omfs_inode *oi)
85 {
86 int xor, i, ofs = 0, count;
87 u16 crc = 0;
88 unsigned char *ptr = (unsigned char *) oi;
89
90 count = be32_to_cpu(oi->i_head.h_body_size);
91 ofs = sizeof(struct omfs_header);
92
93 crc = crc_itu_t(crc, ptr + ofs, count);
94 oi->i_head.h_crc = cpu_to_be16(crc);
95
96 xor = ptr[0];
97 for (i = 1; i < OMFS_XOR_COUNT; i++)
98 xor ^= ptr[i];
99
100 oi->i_head.h_check_xor = xor;
101 }
102
__omfs_write_inode(struct inode * inode,int wait)103 static int __omfs_write_inode(struct inode *inode, int wait)
104 {
105 struct omfs_inode *oi;
106 struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
107 struct buffer_head *bh, *bh2;
108 u64 ctime;
109 int i;
110 int ret = -EIO;
111 int sync_failed = 0;
112
113 /* get current inode since we may have written sibling ptrs etc. */
114 bh = omfs_bread(inode->i_sb, inode->i_ino);
115 if (!bh)
116 goto out;
117
118 oi = (struct omfs_inode *) bh->b_data;
119
120 oi->i_head.h_self = cpu_to_be64(inode->i_ino);
121 if (S_ISDIR(inode->i_mode))
122 oi->i_type = OMFS_DIR;
123 else if (S_ISREG(inode->i_mode))
124 oi->i_type = OMFS_FILE;
125 else {
126 printk(KERN_WARNING "omfs: unknown file type: %d\n",
127 inode->i_mode);
128 goto out_brelse;
129 }
130
131 oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
132 sizeof(struct omfs_header));
133 oi->i_head.h_version = 1;
134 oi->i_head.h_type = OMFS_INODE_NORMAL;
135 oi->i_head.h_magic = OMFS_IMAGIC;
136 oi->i_size = cpu_to_be64(inode->i_size);
137
138 ctime = inode_get_ctime_sec(inode) * 1000LL +
139 ((inode_get_ctime_nsec(inode) + 999)/1000);
140 oi->i_ctime = cpu_to_be64(ctime);
141
142 omfs_update_checksums(oi);
143
144 mark_buffer_dirty(bh);
145 if (wait) {
146 sync_dirty_buffer(bh);
147 if (buffer_req(bh) && !buffer_uptodate(bh))
148 sync_failed = 1;
149 }
150
151 /* if mirroring writes, copy to next fsblock */
152 for (i = 1; i < sbi->s_mirrors; i++) {
153 bh2 = omfs_bread(inode->i_sb, inode->i_ino + i);
154 if (!bh2)
155 goto out_brelse;
156
157 memcpy(bh2->b_data, bh->b_data, bh->b_size);
158 mark_buffer_dirty(bh2);
159 if (wait) {
160 sync_dirty_buffer(bh2);
161 if (buffer_req(bh2) && !buffer_uptodate(bh2))
162 sync_failed = 1;
163 }
164 brelse(bh2);
165 }
166 ret = (sync_failed) ? -EIO : 0;
167 out_brelse:
168 brelse(bh);
169 out:
170 return ret;
171 }
172
omfs_write_inode(struct inode * inode,struct writeback_control * wbc)173 static int omfs_write_inode(struct inode *inode, struct writeback_control *wbc)
174 {
175 return __omfs_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
176 }
177
omfs_sync_inode(struct inode * inode)178 int omfs_sync_inode(struct inode *inode)
179 {
180 return __omfs_write_inode(inode, 1);
181 }
182
183 /*
184 * called when an entry is deleted, need to clear the bits in the
185 * bitmaps.
186 */
omfs_evict_inode(struct inode * inode)187 static void omfs_evict_inode(struct inode *inode)
188 {
189 truncate_inode_pages_final(&inode->i_data);
190 clear_inode(inode);
191
192 if (inode->i_nlink)
193 return;
194
195 if (S_ISREG(inode->i_mode)) {
196 inode->i_size = 0;
197 omfs_shrink_inode(inode);
198 }
199
200 omfs_clear_range(inode->i_sb, inode->i_ino, 2);
201 }
202
omfs_iget(struct super_block * sb,ino_t ino)203 struct inode *omfs_iget(struct super_block *sb, ino_t ino)
204 {
205 struct omfs_sb_info *sbi = OMFS_SB(sb);
206 struct omfs_inode *oi;
207 struct buffer_head *bh;
208 u64 ctime;
209 unsigned long nsecs;
210 struct inode *inode;
211
212 inode = iget_locked(sb, ino);
213 if (!inode)
214 return ERR_PTR(-ENOMEM);
215 if (!(inode->i_state & I_NEW))
216 return inode;
217
218 bh = omfs_bread(inode->i_sb, ino);
219 if (!bh)
220 goto iget_failed;
221
222 oi = (struct omfs_inode *)bh->b_data;
223
224 /* check self */
225 if (ino != be64_to_cpu(oi->i_head.h_self))
226 goto fail_bh;
227
228 inode->i_uid = sbi->s_uid;
229 inode->i_gid = sbi->s_gid;
230
231 ctime = be64_to_cpu(oi->i_ctime);
232 nsecs = do_div(ctime, 1000) * 1000L;
233
234 inode_set_atime(inode, ctime, nsecs);
235 inode_set_mtime(inode, ctime, nsecs);
236 inode_set_ctime(inode, ctime, nsecs);
237
238 inode->i_mapping->a_ops = &omfs_aops;
239
240 switch (oi->i_type) {
241 case OMFS_DIR:
242 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
243 inode->i_op = &omfs_dir_inops;
244 inode->i_fop = &omfs_dir_operations;
245 inode->i_size = sbi->s_sys_blocksize;
246 inc_nlink(inode);
247 break;
248 case OMFS_FILE:
249 inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
250 inode->i_fop = &omfs_file_operations;
251 inode->i_size = be64_to_cpu(oi->i_size);
252 break;
253 }
254 brelse(bh);
255 unlock_new_inode(inode);
256 return inode;
257 fail_bh:
258 brelse(bh);
259 iget_failed:
260 iget_failed(inode);
261 return ERR_PTR(-EIO);
262 }
263
omfs_put_super(struct super_block * sb)264 static void omfs_put_super(struct super_block *sb)
265 {
266 struct omfs_sb_info *sbi = OMFS_SB(sb);
267 kfree(sbi->s_imap);
268 kfree(sbi);
269 sb->s_fs_info = NULL;
270 }
271
omfs_statfs(struct dentry * dentry,struct kstatfs * buf)272 static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
273 {
274 struct super_block *s = dentry->d_sb;
275 struct omfs_sb_info *sbi = OMFS_SB(s);
276 u64 id = huge_encode_dev(s->s_bdev->bd_dev);
277
278 buf->f_type = OMFS_MAGIC;
279 buf->f_bsize = sbi->s_blocksize;
280 buf->f_blocks = sbi->s_num_blocks;
281 buf->f_files = sbi->s_num_blocks;
282 buf->f_namelen = OMFS_NAMELEN;
283 buf->f_fsid = u64_to_fsid(id);
284
285 buf->f_bfree = buf->f_bavail = buf->f_ffree =
286 omfs_count_free(s);
287
288 return 0;
289 }
290
291 /*
292 * Display the mount options in /proc/mounts.
293 */
omfs_show_options(struct seq_file * m,struct dentry * root)294 static int omfs_show_options(struct seq_file *m, struct dentry *root)
295 {
296 struct omfs_sb_info *sbi = OMFS_SB(root->d_sb);
297 umode_t cur_umask = current_umask();
298
299 if (!uid_eq(sbi->s_uid, current_uid()))
300 seq_printf(m, ",uid=%u",
301 from_kuid_munged(&init_user_ns, sbi->s_uid));
302 if (!gid_eq(sbi->s_gid, current_gid()))
303 seq_printf(m, ",gid=%u",
304 from_kgid_munged(&init_user_ns, sbi->s_gid));
305
306 if (sbi->s_dmask == sbi->s_fmask) {
307 if (sbi->s_fmask != cur_umask)
308 seq_printf(m, ",umask=%o", sbi->s_fmask);
309 } else {
310 if (sbi->s_dmask != cur_umask)
311 seq_printf(m, ",dmask=%o", sbi->s_dmask);
312 if (sbi->s_fmask != cur_umask)
313 seq_printf(m, ",fmask=%o", sbi->s_fmask);
314 }
315
316 return 0;
317 }
318
319 static const struct super_operations omfs_sops = {
320 .write_inode = omfs_write_inode,
321 .evict_inode = omfs_evict_inode,
322 .put_super = omfs_put_super,
323 .statfs = omfs_statfs,
324 .show_options = omfs_show_options,
325 };
326
327 /*
328 * For Rio Karma, there is an on-disk free bitmap whose location is
329 * stored in the root block. For ReplayTV, there is no such free bitmap
330 * so we have to walk the tree. Both inodes and file data are allocated
331 * from the same map. This array can be big (300k) so we allocate
332 * in units of the blocksize.
333 */
omfs_get_imap(struct super_block * sb)334 static int omfs_get_imap(struct super_block *sb)
335 {
336 unsigned int bitmap_size, array_size;
337 int count;
338 struct omfs_sb_info *sbi = OMFS_SB(sb);
339 struct buffer_head *bh;
340 unsigned long **ptr;
341 sector_t block;
342
343 bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
344 array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
345
346 if (sbi->s_bitmap_ino == ~0ULL)
347 goto out;
348
349 sbi->s_imap_size = array_size;
350 sbi->s_imap = kcalloc(array_size, sizeof(unsigned long *), GFP_KERNEL);
351 if (!sbi->s_imap)
352 goto nomem;
353
354 block = clus_to_blk(sbi, sbi->s_bitmap_ino);
355 if (block >= sbi->s_num_blocks)
356 goto nomem;
357
358 ptr = sbi->s_imap;
359 for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
360 bh = sb_bread(sb, block++);
361 if (!bh)
362 goto nomem_free;
363 *ptr = kmemdup(bh->b_data, sb->s_blocksize, GFP_KERNEL);
364 if (!*ptr) {
365 brelse(bh);
366 goto nomem_free;
367 }
368 if (count < sb->s_blocksize)
369 memset((void *)*ptr + count, 0xff,
370 sb->s_blocksize - count);
371 brelse(bh);
372 ptr++;
373 }
374 out:
375 return 0;
376
377 nomem_free:
378 for (count = 0; count < array_size; count++)
379 kfree(sbi->s_imap[count]);
380
381 kfree(sbi->s_imap);
382 nomem:
383 sbi->s_imap = NULL;
384 sbi->s_imap_size = 0;
385 return -ENOMEM;
386 }
387
388 struct omfs_mount_options {
389 kuid_t s_uid;
390 kgid_t s_gid;
391 int s_dmask;
392 int s_fmask;
393 };
394
395 enum {
396 Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask,
397 };
398
399 static const struct fs_parameter_spec omfs_param_spec[] = {
400 fsparam_uid ("uid", Opt_uid),
401 fsparam_gid ("gid", Opt_gid),
402 fsparam_u32oct ("umask", Opt_umask),
403 fsparam_u32oct ("dmask", Opt_dmask),
404 fsparam_u32oct ("fmask", Opt_fmask),
405 {}
406 };
407
408 static int
omfs_parse_param(struct fs_context * fc,struct fs_parameter * param)409 omfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
410 {
411 struct omfs_mount_options *opts = fc->fs_private;
412 int token;
413 struct fs_parse_result result;
414
415 /* All options are ignored on remount */
416 if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE)
417 return 0;
418
419 token = fs_parse(fc, omfs_param_spec, param, &result);
420 if (token < 0)
421 return token;
422
423 switch (token) {
424 case Opt_uid:
425 opts->s_uid = result.uid;
426 break;
427 case Opt_gid:
428 opts->s_gid = result.gid;
429 break;
430 case Opt_umask:
431 opts->s_fmask = opts->s_dmask = result.uint_32;
432 break;
433 case Opt_dmask:
434 opts->s_dmask = result.uint_32;
435 break;
436 case Opt_fmask:
437 opts->s_fmask = result.uint_32;
438 break;
439 default:
440 return -EINVAL;
441 }
442
443 return 0;
444 }
445
446 static void
omfs_set_options(struct omfs_sb_info * sbi,struct omfs_mount_options * opts)447 omfs_set_options(struct omfs_sb_info *sbi, struct omfs_mount_options *opts)
448 {
449 sbi->s_uid = opts->s_uid;
450 sbi->s_gid = opts->s_gid;
451 sbi->s_dmask = opts->s_dmask;
452 sbi->s_fmask = opts->s_fmask;
453 }
454
omfs_fill_super(struct super_block * sb,struct fs_context * fc)455 static int omfs_fill_super(struct super_block *sb, struct fs_context *fc)
456 {
457 struct buffer_head *bh, *bh2;
458 struct omfs_super_block *omfs_sb;
459 struct omfs_root_block *omfs_rb;
460 struct omfs_sb_info *sbi;
461 struct inode *root;
462 struct omfs_mount_options *parsed_opts = fc->fs_private;
463 int ret = -EINVAL;
464 int silent = fc->sb_flags & SB_SILENT;
465
466 sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
467 if (!sbi)
468 return -ENOMEM;
469
470 sb->s_fs_info = sbi;
471
472 omfs_set_options(sbi, parsed_opts);
473
474 sb->s_maxbytes = 0xffffffff;
475
476 sb->s_time_gran = NSEC_PER_MSEC;
477 sb->s_time_min = 0;
478 sb->s_time_max = U64_MAX / MSEC_PER_SEC;
479
480 sb_set_blocksize(sb, 0x200);
481
482 bh = sb_bread(sb, 0);
483 if (!bh)
484 goto end;
485
486 omfs_sb = (struct omfs_super_block *)bh->b_data;
487
488 if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
489 if (!silent)
490 printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
491 omfs_sb->s_magic);
492 goto out_brelse_bh;
493 }
494 sb->s_magic = OMFS_MAGIC;
495
496 sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
497 sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
498 sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
499 sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
500 sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
501 mutex_init(&sbi->s_bitmap_lock);
502
503 if (sbi->s_num_blocks > OMFS_MAX_BLOCKS) {
504 printk(KERN_ERR "omfs: sysblock number (%llx) is out of range\n",
505 (unsigned long long)sbi->s_num_blocks);
506 goto out_brelse_bh;
507 }
508
509 if (sbi->s_sys_blocksize > PAGE_SIZE) {
510 printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
511 sbi->s_sys_blocksize);
512 goto out_brelse_bh;
513 }
514
515 if (sbi->s_blocksize < sbi->s_sys_blocksize ||
516 sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
517 printk(KERN_ERR "omfs: block size (%d) is out of range\n",
518 sbi->s_blocksize);
519 goto out_brelse_bh;
520 }
521
522 /*
523 * Use sys_blocksize as the fs block since it is smaller than a
524 * page while the fs blocksize can be larger.
525 */
526 sb_set_blocksize(sb, sbi->s_sys_blocksize);
527
528 /*
529 * ...and the difference goes into a shift. sys_blocksize is always
530 * a power of two factor of blocksize.
531 */
532 sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
533 get_bitmask_order(sbi->s_sys_blocksize);
534
535 bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));
536 if (!bh2)
537 goto out_brelse_bh;
538
539 omfs_rb = (struct omfs_root_block *)bh2->b_data;
540
541 sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
542 sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
543
544 if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
545 printk(KERN_ERR "omfs: block count discrepancy between "
546 "super and root blocks (%llx, %llx)\n",
547 (unsigned long long)sbi->s_num_blocks,
548 (unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
549 goto out_brelse_bh2;
550 }
551
552 if (sbi->s_bitmap_ino != ~0ULL &&
553 sbi->s_bitmap_ino > sbi->s_num_blocks) {
554 printk(KERN_ERR "omfs: free space bitmap location is corrupt "
555 "(%llx, total blocks %llx)\n",
556 (unsigned long long) sbi->s_bitmap_ino,
557 (unsigned long long) sbi->s_num_blocks);
558 goto out_brelse_bh2;
559 }
560 if (sbi->s_clustersize < 1 ||
561 sbi->s_clustersize > OMFS_MAX_CLUSTER_SIZE) {
562 printk(KERN_ERR "omfs: cluster size out of range (%d)",
563 sbi->s_clustersize);
564 goto out_brelse_bh2;
565 }
566
567 ret = omfs_get_imap(sb);
568 if (ret)
569 goto out_brelse_bh2;
570
571 sb->s_op = &omfs_sops;
572
573 root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
574 if (IS_ERR(root)) {
575 ret = PTR_ERR(root);
576 goto out_brelse_bh2;
577 }
578
579 sb->s_root = d_make_root(root);
580 if (!sb->s_root) {
581 ret = -ENOMEM;
582 goto out_brelse_bh2;
583 }
584 printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
585
586 ret = 0;
587 out_brelse_bh2:
588 brelse(bh2);
589 out_brelse_bh:
590 brelse(bh);
591 end:
592 if (ret)
593 kfree(sbi);
594 return ret;
595 }
596
omfs_get_tree(struct fs_context * fc)597 static int omfs_get_tree(struct fs_context *fc)
598 {
599 return get_tree_bdev(fc, omfs_fill_super);
600 }
601
602 static void omfs_free_fc(struct fs_context *fc);
603
604 static const struct fs_context_operations omfs_context_ops = {
605 .parse_param = omfs_parse_param,
606 .get_tree = omfs_get_tree,
607 .free = omfs_free_fc,
608 };
609
omfs_init_fs_context(struct fs_context * fc)610 static int omfs_init_fs_context(struct fs_context *fc)
611 {
612 struct omfs_mount_options *opts;
613
614 opts = kzalloc(sizeof(*opts), GFP_KERNEL);
615 if (!opts)
616 return -ENOMEM;
617
618 /* Set mount options defaults */
619 opts->s_uid = current_uid();
620 opts->s_gid = current_gid();
621 opts->s_dmask = opts->s_fmask = current_umask();
622
623 fc->fs_private = opts;
624 fc->ops = &omfs_context_ops;
625
626 return 0;
627 }
628
omfs_free_fc(struct fs_context * fc)629 static void omfs_free_fc(struct fs_context *fc)
630 {
631 kfree(fc->fs_private);
632 }
633
634 static struct file_system_type omfs_fs_type = {
635 .owner = THIS_MODULE,
636 .name = "omfs",
637 .kill_sb = kill_block_super,
638 .fs_flags = FS_REQUIRES_DEV,
639 .init_fs_context = omfs_init_fs_context,
640 .parameters = omfs_param_spec,
641 };
642 MODULE_ALIAS_FS("omfs");
643
init_omfs_fs(void)644 static int __init init_omfs_fs(void)
645 {
646 return register_filesystem(&omfs_fs_type);
647 }
648
exit_omfs_fs(void)649 static void __exit exit_omfs_fs(void)
650 {
651 unregister_filesystem(&omfs_fs_type);
652 }
653
654 module_init(init_omfs_fs);
655 module_exit(exit_omfs_fs);
656